Tyres deflating too quickly

[darkfriend]

Hi all,

I've had my 118TSi for almost a year now and have always noticed that the tyres deflate rather quickly. I recently bought a portable tyre pressure monitor and found that all four tyres lost 10kpa in five days! I need to fill up my tyres more than I fill up my tank!

I tend now to fill them to 250kpa so I can go about two weeks without having to top them up.

Anyone else notice this? Is it likely that the tyres are poorly fitted or that the valves are crap or something else? I drive like a grandma (almost) and the roads here are in good nic.

Any ideas welcome.

Thanks

[triode12]

Buckled rims?

[darkfriend]

I don't think so. They have always done this... and it's all wheels

[Corey_R]

Maybe there's too much oxygen in your air

Try Nitrogen

[Ozram]

Put some washing up liquid in a spray bottle with water and squirt around the tyre bead (where it meets the wheel). But especially where the valve goes through the wheel and under the valve cap where the Schrader valve is. See if it bubbles up.

[Andych]

Would Helium reduce the unspung weight?

[brad]

Could be a number of things

• leaky valves
• leak around the valves
• leaky beads
• porous tyres
• porous rims
• punctures

check the valve & the valve cap.

If you have a swimming pool, take the tyre/rim off the car & put it in the pool & check for bubbles - might take 15 minutes of observation.

Check the tread area for nails, screws, glass & other foreign objects.

Possibly you'll have to get new tubeless valves or get the rims/beads cleaned & re-seated.

Nitrogen might help a fraction but it would be worth while to mention your issues to a tyre specialist & get them to monitor for a while & give their opinion. The tyres might be claimable if they are badly porous.

What do you actually mean by "a portable tyre pressure monitor"?? Photos please.

BTW 10kPa is 1.4PSI isn't it? You'd lose that if you don't do a clean attach of the pressure gauge.

[Idle]

Many years ago that was par for the course, but the wheels and tyres we get nowadays shouldn't lose pressure so quickly — something isn't right.

May be poorly fitted valves (the valves themselves won't leak if the caps are screwed down firmly), poor quality/badly fitted tyres or possibly even porous rims.

Both our cars (2YO Mk 6 TDI & Yaris with alloys) get their tyres kicked occasionally, checked monthly, rarely need topping up and when they do it's only a puff.

The Cressida and Corolla before them were much the same when new, although they did need topping up more often once their original Japanese tyres (Dunlop (Sumitomo) on the Cressida, can't recall what the Corolla had) were replaced with local products— of course, all car tyres are now imported, no longer any choice.

[shakespeare]

May be a silly question but are you checking the pressure when it's cold or warm? The variations can be quite dramatic, even an ambient temp variance can cause slight pressure variations, however I wouldn't worry to much with 1 psi, 10 psi would be a concern and you'd most likely then have nail/screw embedded!

[Busby]

I had a similar issue so took it to bjane tmarts and apparently (so i was told) they'll always go down as rubber is slightly porous. Bloke reckoned nitro would fix that (molecules are bigger than oxygen) so gave it a crack. Man I tell you it's the shizzle! I've had it now for a few weeks and it ain't going back to oxygen. I run 18 detroits and the ride is so much better.. Swear it's quieter too. Apparently nitro is more stabile as well as runs cooler so handling is better.. However it's $10 a corner though.. Still worth it I reckon. Plus the red caps look pretty sweet